package com.atguigu.flink.chapter07;

import com.atguigu.flink.bean.WaterSensor;
import org.apache.flink.api.common.functions.AggregateFunction;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.windowing.ProcessWindowFunction;
import org.apache.flink.streaming.api.windowing.assigners.TumblingProcessingTimeWindows;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.api.windowing.windows.TimeWindow;
import org.apache.flink.util.Collector;

/**
 * @Author lizhenchao@atguigu.cn
 * @Date 2021/9/17 9:24
 */
public class Flink07_Window_Aggregate {
    public static class Avg {
        public Integer vcSum = 0;
        public Long count = 0L;
        
        public Double avg() {
            return this.vcSum * 1.0 / count;
        }
    }
    
    public static void main(String[] args) {
        Configuration conf = new Configuration();
        conf.setInteger("rest.port", 20000);
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment(conf);
        env.setParallelism(2);
        
        env
            .socketTextStream("hadoop162", 9999)
            .map(line -> {
                String[] data = line.split(",");
                return new WaterSensor(data[0], Long.valueOf(data[1]), Integer.valueOf(data[2]));
            })
            .keyBy(WaterSensor::getId)
            .window(TumblingProcessingTimeWindows.of(Time.seconds(4)))
            .aggregate(
                new AggregateFunction<WaterSensor, Avg, Double>() {
                    // 创建累加器: 初始化一个累加器
                    @Override
                    public Avg createAccumulator() {
                        System.out.println("Flink07_Window_Aggregate.createAccumulator");
                        return new Avg();
                    }
    
                    // 对传入的值进行累加
                    @Override
                    public Avg add(WaterSensor value, Avg acc) {
                        System.out.println("Flink07_Window_Aggregate.add");
                        acc.vcSum += value.getVc();
                        acc.count++;
                        return acc;
                    }
    
                    // 返回最终的结果
                    @Override
                    public Double getResult(Avg acc) {
                        System.out.println("Flink07_Window_Aggregate.getResult");
                        return acc.avg();
                    }
    
                    // 合并累加器. 这个方法只有当窗口是会话窗口的时候才会触发
                    @Override
                    public Avg merge(Avg a, Avg b) {
                        System.out.println("Flink07_Window_Aggregate.merge");
                        return null;
                    }
                },
                new ProcessWindowFunction<Double, String, String, TimeWindow>() {
                    @Override
                    public void process(String key,
                                        Context ctx,
                                        Iterable<Double> elements,
                                        Collector<String> out) throws Exception {
    
                        Double result = elements.iterator().next();
                        out.collect(key + " 平均水位: " + result);
                    }
                }
            )
            .print();
        
        try {
            env.execute();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
